Space Sunday: China’s ambitions, telescopes and SLS

Sunrise as seen from the Tianhe core module of China’s Tinagong space station ahead of the arrival of Shenzhou-12. Credit: China National Space Administration / China State Media

Shenzhou-12, China’s first crewed mission to orbit in almost 5 years, lifted-off from the Jiuquan Satellite Launch Centre in northwest China at 01:22 UTC on the morning of Thursday, June 17th, heading towards the Tianhe core module of the country’s new space station.

Carried aloft by a Long March 2F booster, the mission comprises three taikonauts Nie Haisheng (mission commander) and Liu Boming, both of whom have previously flown in space, and rookie  Tang Hongbo. Together, they will spend three months at the space station, putting it through a series of commissioning tests and operations.

The Long March 2F carrying Shenzhou-12 mission lifts-off from the Jiuquan Satellite Launch Centre, June 17th (UTC), 2021. Credit: China Stat Media

Following launch, the Shenzhou vehicle performed a rapid chase-and-catch with the Tianhe module, docking with it some 6 hours 32 minutes later. In doing so, it became the second vehicle to dock with the module, the first being the Tianzhou-2 resupply vehicle which delivered essential supplies and equipment to the fledgling space station at the end of May 2021.

Overall, Shenzhou-12 is the the third of eleven flights China has planned between now and the end of 2022 in order to complete the Tinagong station, the first having been the Tinahe module itself. These launches will include two science modules and additional Shenzhou crew and Tianzhou resupply missions.

The Shenzhou-12 crew aboard Tianhe. Form left to right: Tang Hongbo, mission commander  Nie Haisheng and Liu Boming. Credit: China State Media

The flight of Shenzhou-12 also marked the first time China has used the chase-and-catch approach to orbital rendezvous. It is a technique both Russia and the United States have started to employ in order to more quickly deliver cosmonauts and astronauts to the International Space Station; for China, it meant reducing a typical two-day rendezvous time seen with the earlier Tiangong orbital laboratories to just the 6+ hours seen in this flight.

Prior to launch, the crew were treated to a parade and celebration by members of the People’s Liberation Army and their families (there is no real civil / military distinction in China’s human spaceflight operations), whilst their arrival and boarding the Tinahe marked the first time since May 2000 that two orbiting space stations have been simultaneously inhabited – back then it was the ISS and Russia’s soon-to-be-decommissioned Mir. Now it is the ISS and the nascent Tiangong station.

Ahead of the launch and during an international conference on space development, China joined with Russia in formally announcing the International Lunar Research Station (ILRS), intended to serve as ” a comprehensive scientific experiment base built on the lunar surface and on [sic] the lunar orbit”, inviting international partners to join them.

ILRS is seen as something of a competitor to the American-led Artemis programme, and during the presentation  representatives of Russia’s Roscosmos and the China National Space Administration (CNSA) indicated that ILRS will (like Artemis) combine a Moon-orbiting space station with a surface base in the lunar south polar region.

First announced in March 2021, after Russia rejected US overtures to be a part of Artemis, the ILRS looks set to undergo a rapid cycle of development. China and Russia anticipate working together between 2021 and 2025 to select the preferred location for the lunar base, with actual deployment and construction to commence in 2026 and continue through until 2036. During the construction phase, the two countries plan to place a station into cislunar space which will act as a waystation between their orbital facilities in Earth orbit and the lunar base (China will use their Tiangong station at the “earth end” for flights to / from the Moon, and Russia will use its recently-announced new space station, which it intends to have operational by 2030).

An artist’s impression of the Russia-China ILRS, showing the main pressurised facilities in the foreground, solar power facilities to the right and communications arrays in the background. Credit: Roscosmos / CNSA

According to both countries, the focus of ILRS will be to “carry out multi-disciplinary and multi-objective scientific research activities including exploration and utilisation, and lunar-based observation.” They further indicated that the European Space Agency (ESA), Thailand, the United Arab Emirates and Saudi Arabia have all declared an interest in joining the project.

And if that weren’t enough, China has also announced it intends to develop the means to establish a long-term / permanent human presence on Mars.

Speaking at the same event at which the ILRS was officially confirmed, Wang Xiaojing, president of the China Academy of Launch Vehicle Technology (CALT), unveiled an ambitious programme that would see China extend is robotic exploration of Mars before moving to more extended automated missions using chemical rockets to deliver ISRU (in-situ resource utilisation) missions for the production of air, water and fuel through locally-available resources. From there, Wan indicated the country would start delivering payload missions to Mars aimed at supporting a human presence.

For actual crewed missions, Wan said China would use nuclear-powered “ferries” operating between Earth and Mars, dramatically reducing flight times. Built in Earth orbit, these would eventually become “cyclers”, with two or possibly three craft looping between the two planets, with crews and their equipment launching from Earth to join one for the trip to Mars, and then at the end of their mission hitching a ride home on another of the ferries as it swings around Mars.

No time frames for when all this might happen were given, and China has a huge mountain to climb in terms of technology development – ISRU system, life support systems, operating human missions in deep space (and with suitable solar / cosmic radiation protection). It also has to develop the planned nuclear thermal engines the “ferries” would use and gain experience in operating them and ensuring they don’t add radiation exposure risks to crews . All of this, coupled with the ILRS plans, likely means China will not be in a position to undertake any kind of human mission to Mars before the 2040s, even if Wan’s presentation turns into a programme.

Space Telescopes: Hubble Hits Computer Hitch; NEOSM Moves Forward

Spacecraft controllers are continuing to bring science missions on the Hubble Space Telescope (HST) back on-line after a fault with a computer memory module caused the telescope to switch to a safe module of operations.

The module, one of four on the telescope’s payload computer that is used to manage science instrument operations, stopped responding to commands on Sunday, June 13th. NASA initially intended to switch operations through one of the computer’s remaining three 64 Kb (yes, kilobtye) modules on June 17th. However, on June 18th, the agency indicated the second module failed to initiate correctly, and the decision had been taken to leave Hubble in its safe mode while the issue is further analysed.

Cutaway of the Hubble Space Telescope. And main computer systems, including the problematic payload computer, are located in the bay around the science instruments bay. Credit: NASA / ESA

The computer only requires one of the four modules to be operational – and the computer itself has a back-up; but before any move is made to try to initialise an additional module on the primary computer or make a switch to the secondary,  engineers would like to identify the root cause for the second module failing to initialise.

In the meantime, NASA remains confident this latest issue with its 31-year-old flagship telescope can be fixed, and demand for time with the telescope continues to grow from science and astronomical institutions from around the world. So much so, that even with James Webb scheduled for launch (Ariane launcher allowing) at the end of 2021, and the Nancy Grace Roman telescope due to launch in 2025 – both of which will take over a portion of Hubble’s work -, plans are already being put forward to keep some of the instruments on HST operating through until the end of the 2030s.

We do have anomalies. That happens when you have a decades-old observatory, but we have been able to resolve those anomalies.

– Nancy Levenson, deputy director of the Space Telescope Science Institute

As  well and the upcoming “big” space telescopes – Nancy Grace Roman (formerly the W-FIRST) and James Webb Space Telescope, NASA is moving forward with NEOSM – the Near Earth Object (NEO) Surveyor Mission, which is intended to seek out and help track asteroids that cross Earth’s orbit as they travel around the Sun, and thus present the potential for a possible future collision with our planet.

NEOSM showing the large rear sun screen facing the Sun, and the grey instrument housing and communications dish facing towards Earth. Credit: NASA

NEOSM is an infra-red telescope destined to be launched in 2026 and placed in a heliocentric (Sun-centred) orbit at the Sun-Earth L1 position (that is, orbiting the Sun been it and Earth at a point in space where the gravitational influence of star and planet are in equilibrium). Once in position, NEOSM will operate for a planned 12 years.

The project is actually a re-vamp of a proposal called Near-Earth Object Camera (NEOCam), put forward in the 2010s, but which was not ultimately selected in the 2017 round of Discovery mission funding.  However, while not funded, NASA used discretionary funding to allow studies into the concept to continue, allowing it to morph into NEOSM in 2019, with NASA removing it from competitive Discovery funding to allow it to be financed directly, funds allowing.

The increased budgets for NASA with their emphasis on space / Earth science means that the required funding is now in place to allow NEOSM to move to “phase B” development. This will allow the telescope’s design and mission parameters to be finalised, potentially clearing the way for construction to commence in 2023.

Earth-crossing NEOs have been a known threat for decades, and much has been done from Earth-based observations to locate and track many of the larger asteroids (150+ metres across) that could present a real threat to population centres – or even to all life on Earth in the case of the larger ones – should they actually impact our planet. However, as we’re frequently reminded, there are still asteroids we are only spotting as or just after they skim by Earth. There are potentially also thousands of asteroids between 90 and 150 metres across which could be a danger to local populations and which are next to impossible to find using night-time only, ground-based observations.

NEOSM is specifically designed to hunt for the latter. Sitting in the L1 position, it will have the Sun behind it, illuminating Earth and the space around it – and most importantly heating any small asteroids entering that space, allowing the telescope’s infra-red imager to spot them.

Each night, astronomers across the globe diligently use ground-based optical telescopes to discover new NEOs, characterise their shape and size, and confirm they do not pose a threat to us. Those telescopes are only able to look for NEOs in the night sky. NEO Surveyor would allow observations to continue day and night, specifically targeting regions where NEOs that could pose a hazard might be found.  

– Kelly Fast, manager of NASA’s NEO Observations Programme

Overall, NEOSM is expected to cost US $811 million in development and launch costs between 2021 and 2026, of which US  $28.3 million will come from NASA’s 2021 budget and US $143.2 million in the 2022 budget.

Stacking SLS

In May 2021, the core stage of NASA’s first Space Launch System (SLS) rocket arrived at Kennedy Space Centre, where it was transferred to the massive Vehicle Assembly Building (VAB) – see Space Sunday: Starships, Helicopter and Rockets.

The two advanced solid rocket boosters (SRBs) that will also power the SLS towards orbit had been stacked on a mobile launch platform within on of the VAB’s cavernous high bays ahead of the core stage arriving, and over the course of two days – June 12th and 13th, the core was moved to join them.

A view up into the heights of the VAB from the mobile launch platform that will carry NASA’s first Space Launch System rocket to the launch pad. The Solid Rocket Boosters can be seen on either side. Credit: NASA

This involved a complex operation that first required the stage – sitting within the second VAB high bay to be horizontally lift clear of its carrying cradle, and then the entire 64.6 metre tall, 8.4 metre wide, 85-tonne stage raised to the vertical position.

With this completed, the stage then had to be raised more than its own height up into the rafters of the VAB, and then transferred laterally into the high bay containing the SRBs and launch platform. Once there, and correctly aligned, the core could then be slowly lowered between the SRBs and secured onto the launch platform, and then the two SRBs connected to it.

The SLS core stage being lowered between the two SRBs on June 13th. Credit: NASA

The next phase of stacking will see the interconnect between the core and upper stages  mounted on the top of the core stage  before the upper stage – called the Interim Cryogenic Propulsion Stage (ICPS) is added. A further interconnect will then be put in place, and the Orion vehicle payload stacked onto that to complete the vehicle.

The vehicle is due to lift-off before the end of the year as the Artemis 1 mission, designed to send an uncrewed, fully automated Orion vehicle on an extended trip around the Moon to check-out all of its flight and navigation systems, and then bring it back to Earth to test its entry and descent system through re-entry into Earth’s atmosphere at the speeds experienced by returning lunar missions (around Mach 25, compared to Mach 17 for Earth orbital re-entries). Providing it is successful, Artemis 2 will carry out a similar flight in 2023, but with a crew aboard the Orion vehicle.

In the meantime, NASA issued a time-lapse film of the entire operation.